#include <stdio.h>

#define max(a,b) (((a)>(b))?(a):(b))
#define max3(a,b,c) max(max(a,b),c)

int main()
{
    int a,b,c;
    scanf("%d %d %d",&a,&b,&c);

    float m = (float)max3(a+b,b,c)/(max3(a,b+c,c)+max3(a,b,b+c));
    printf("%.2f\n",m);
}
